President Barack Obama released a statement Saturday on Democratic Iowa Sen. Tom Harkin's announcement that he would not seek re-election.

"By the time Senator Harkin finishes his fifth term, he will have represented the people of Iowa in the United States Congress for an incredible 40 years," Obama said. "He has served in the U.S. Senate longer than any Democrat in Iowa's history. During his tenure, he has fought passionately to improve quality of life for Americans with disabilities and their families, to reform our education system and ensure that every American has access to affordable health care. Senator Harkin will be missed, and Michelle and I join Iowans in thanking him for his long-standing service and wish him and his wife, Ruth, all the best in the future."